Ellagic acid microspheres restrict the growth of Babesia and Theileria in vitro and Babesia microti in vivo

BackgroundThere are no effective vaccines against Babesia and Theileria parasites; therefore, therapy depends heavily on antiprotozoal drugs. Treatment options for piroplasmosis are limited; thus, the need for new antiprotozoal agents is becoming increasingly urgent. Ellagic acid (EA) is a polyphenol found in various plant products and has antioxidant, antibacterial and effective antimalarial activity in vitro and in vivo without toxicity. The present study documents the efficacy of EA and EA-loaded nanoparticles (EA-NPs) on the growth of Babesia and Theileria.MethodsIn this study, the inhibitory effect of EA, -cyclodextrin ellagic acid (-CD EA) and antisolvent precipitation with a syringe pump prepared ellagic acid (APSP EA) was evaluated on four Babesia species and Theileria equi in vitro, and on the multiplication of B. microti in mice. The cytotoxicity assay was tested on Madin-Darby bovine kidney (MDBK), mouse embryonic fibroblast (NIH/3T3) and human foreskin fibroblast (HFF) cell lines.ResultsThe half-maximal inhibitory concentration (IC50) values of EA and -CD EA on B. bovis, B. bigemina, B. divergens, B. caballi and T. equi were 9.581.47, 7.87 +/- 5.8, 5.41 +/- 2.8, 3.29 +/- 0.42 and 7.46 +/- 0.6 mu M and 8.8 +/- 0.53, 18.9 +/- 0.025, 11 +/- 0.37, 4.4 +/- 0.6 and 9.1 +/- 1.72 mu M, respectively. The IC50 values of APSP EA on B. bovis, B. bigemina, B. divergens, B. caballi and T. equi were 4.2 +/- 0.42, 9.6 +/- 0.6, 2.6 +/- 1.47, 0.92 +/- 5.8 and 7.3 +/- 0.54 mu M, respectively. A toxicity assay showed that EA, -CD EA and APSP EA affected the viability of cells with a half-maximal effective concentration (EC50) higher than 800 mu M. In the experiments on mice, APSP EA at a concentration of 70 mg/kg reduced the peak parasitemia of B. microti by 68.1%. Furthermore, the APSP EA-atovaquone (AQ) combination showed a higher chemotherapeutic effect than that of APSP EA monotherapy.Conclusions p id=Par4 To our knowledge, this is the first study to demonstrate the in vitro and in vivo antibabesial action of EA-NPs and thus supports the use of nanoparticles as an alternative antiparasitic agent.